WTXS32 PGTW 070900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 010// RMKS/ 1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 010 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 070600Z --- NEAR 16.0S 105.7E MOVEMENT PAST SIX HOURS - 360 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 16.0S 105.7E --- FORECASTS: 12 HRS, VALID AT: 071800Z --- 15.3S 105.8E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 025 DEG/ 04 KTS --- 24 HRS, VALID AT: 080600Z --- 14.5S 106.2E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 060 DEG/ 07 KTS --- 36 HRS, VALID AT: 081800Z --- 13.8S 107.4E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 095 DEG/ 13 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 090600Z --- 14.0S 110.0E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 160 DEG/ 13 KTS --- 72 HRS, VALID AT: 100600Z --- 18.8S 111.8E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 185 DEG/ 14 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 110600Z --- 24.3S 111.3E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 070900Z POSITION NEAR 15.8S 105.7E. 07APR21. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED APPROXIMATELY 608 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED NORTHWARD AT 04 KNOTS OVER THE PAST SIX HOURS. MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERY WELL-DEFINED, COMPACT AND PARTIALLY EXPOSED LOW LEVEL VORTEX DISPLACED NORTHEAST OF DEEP FLARING CONVECTION. THE INITIAL POSITION IS SET WITH HIGH CONFIDENCE BASED ON THE EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) IN ANIMATED VISIBLE IMAGERY. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE, SLIGHTLY HIGHER THAN A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.5 (35 KTS) BASED ON AN ADT ESTIMATE OF T3.1 (46 KTS) AND A SATCON ESTIMATE OF 44 KNOTS. TC 27S IS ENSCONCED IN A MARGINAL ENVIRONMENT WITH A MODERATE (15-20 KTS) EASTERLY VWS INDUCED FROM THE GENERAL EAST-NORTHEASTERLY ENVIRONMENTAL FLOW ALOFT AS WELL AS OUTFLOW FROM TC 26S TO THE NORTHEAST. WHILE SHEAR IS MODERATE, IT IS BEING OFFSET SOMEWHAT BY ROBUST POLEWARD OUTFLOW AND WARM SSTS. TC 27S IS FORECAST TO CONTINUE TRACKING SLOWLY NORTHWARD OVER THE NEXT 24 HOURS UNDER GENERALLY WEAK STEERING CONDITIONS, BUT WILL TURN EAST BY TAU 36 AS IT MOVES WITHIN 350NM OF TC 26S AND IS CAPTURED BY THE LARGER SYSTEM. ONCE CAPTURED, TC 27S WILL BEGIN BINARY INTERACTION WITH TC 26S, RAPIDLY ACCELERATING AROUND TO A SOUTHEASTWARD AND THEN SOUTHWARD TRACK BETWEEN TAU 48 THROUGH TAU 96. THE TWO SYSTEMS WILL MOVE TO WITHIN 170NM OF ONE ANOTHER BY TAU 72 AND TC 27S WILL BEGIN TO BECOME ABSORBED BY TC 26S, WITH FULL MERGER EXPECTED NO LATER THAN TAU 96. CURRENT ENVIRONMENTAL CONDITIONS ARE EXPECTED TO PERSIST OVER THE NEXT 24 HOURS, WITH LITTLE TO NO CHANGE IN INTENSITY EXPECTED BEFORE TAU 24. AS THE SYSTEM BEGINS TO MOVE NORTH OF TC 26S IT WILL MOVE INTO AN AREA OF IMPROVED OUTFLOW AND DECREASED VWS, ALLOWING FOR A BRIEF PERIOD OF INTENSIFICATION, TO A PEAK OF 50 KNOTS AT TAU 48. AFTER THIS POINT, THE COMBINATION OF INCREASING VWS AND DISRUPTION OF THE VORTEX DUE TO INTERACTION WITH TC 26S WILL LEAD TO RAPID WEAKENING AFTER TAU 72. DYNAMIC MODEL GUIDANCE IS IN POOR AGREEMENT, AND THE JTWC FORECAST TRACK HAS SHIFTED SLIGHTLY TO THE WEST THAN THE PREVIOUS FORECAST, CLOSE TO THE EGRR SOLUTION. THE GFS, NAVGEM AND ECMWF SOLUTIONS MOVED FURTHER EAST IN THE MID-RANGE OF THE FORECAST BUT ALIGN CLOSELY WITH THE JTWC FORECAST BY TAU 96. CONFIDENCE IN THE TRACK REMAINS LOW DUE TO THE UNCERTAINTY ASSOCIATED WITH THE BINARY INTERACTION WITH TC 26S. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 18 FEET. NEXT WARNINGS AT 071500Z, 072100Z, 080300Z AND 080900Z. REFER TO TROPICAL CYCLONE 26S (SEROJA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY UPDATES.// NNNN